Banks appealed from his guilty plea for possession of a controlled substance after the district court denied his motion to suppress evidence. Officers followed the Nevada statutory “knock and announce” procedures to execute a search warrant by knocking loudly one time on the apartment door and announcing. After a 15- to 20-second delay without a response, the SWAT officers forced entry. They found Banks dripping wet, just emerging from a shower. Banks moved to suppress his statements made during his subsequent interrogation based on a the fact that the officers did not wait a reasonable period of time before forcing entry. The Court of Appeals ruled here that an affirmative refusal of entry is not required by the statute, but that a lapse of an even more substantial amount of time is needed. What constitutes a “reasonable waiting period” includes, but is not limited to: (a) the size of the residence; (b) location of the residence; (c) location of the officers in relation to the main living or sleeping areas of the residence; (d) time of day; (e) nature of the suspected offense; (f) evidence demonstrating the suspect’s guilt; (g) suspect’s prior convictions and, if any, the type of offense for which he was convicted; and (h) any other observations triggering the senses of the officers that reasonably would lead one to believe that immediate entry was necessary. Here the officers knew that sounds transmitted relatively easily. They heard no noise and had no reason to believe that exigent circumstances warranted breaking down the door. They were required to delay acting for a sufficient period of time before they could reasonably conclude that they impliedly had been denied amittance.